Parasitically powered signal source and method

ABSTRACT

A system for monitoring a wellbore including a parasitic power generation configuration, a signal source in operable connection with the parasitic power generation configuration, the source being permanently positioned within the wellbore and capable of providing a signal that is receivable by a separate device to query condition of the wellbore, and method for monitoring the wellbore.

BACKGROUND

In the hydrocarbon recovery industry information about the conditions extant in the subterranean formation and in the bore itself often is regarded as highly important. So important is such information that production from the well is stopped on occasion in order to gain more information through the introduction of sensory tools built for the purpose. This is done even in the face of the significant loss of monetary gain incurred for each stoppage of well production. Generally it is considered that if these shorter stoppages are not incurred, there is a substantial risk of a more significant stoppage to remediate a problem that could have been detected earlier when it was a little problem.

While hydrocarbon recovery operators currently do run efficiently, having a greater access to information without production stoppage would be well received by the art.

SUMMARY

A system for monitoring a wellbore including a parasitic power generation configuration, and a signal source in operable connection with the parasitic power generation configuration, the source being permanently positioned within the wellbore and capable of providing a signal that is receivable by a separate device to query condition of the wellbore.

A method for monitoring a wellbore including generating power parasitically with a parasitic power generation configuration, applying the generated power to a permanently installed signal source, generating a signal from the signal source, reflecting the signal from the wellbore, and receiving the reflected signal with a receiving device.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawing wherein like elements are numbered alike:

FIG. 1 is a schematic illustration of an embodiment of the parasitically powered signal source as disclosed herein.

DETAILED DESCRIPTION

While the art has long used seismic sources to query the wellbore for information particularly during drilling thereof, such information has never been sought on any ongoing basis both because of a lack of recognition of any benefit associated therewith and because of logistical problems surrounding actually making that possible. With respect to the latter, seismic sources require energy to operate, that energy being supplied from surface through wirelines and other similar conduits. These, of course, require an interruption in other well activities to run and in combination with the lack of any appreciation by the art of a value associated with seismic information an a real time or semi real time basis, any configuration so capable has never been pursued.

The present inventors have surmised that tracking seismic (or other signal) variations over time provides significantly beneficial information about the condition of the wellbore on an ongoing basis. This is helpful especially in connection with more contemporary wells that have reserves that are harder to extract from the subterranean formation than wells produced in the past.

Referring to FIG. 1, a schematic view of a parasitically powered signal source system 10 is illustrated. Any type of parasitic power generation configuration 11 may be utilized in connection with the system 10. Depicted in FIG. 1 is but one possible power generation configuration disclosed in U.S. patent application Ser. No. 11/728,760, filed Mar. 27, 2007, entitled “Peizoelectric Resonant Power Generator”, which is fully incorporated herein by reference. Other types of power generation configurations contemplated include but are not limited to flow-actuated turbines, ambient vibration, ambient therma cycling, etc. Schematically depicted in FIG. 1 is a pump jack 12, a sucker rod 14 connected to the pump jack 12 and a borehole 16 in which the sucker rod 14 is reciprocatingly positioned, the borehole further having a seismic source 20 mounted conveniently therewithin. Seismic sources contemplated for use in the system 10 include but are not limited to that disclosed in U.S. patent application publication number 2006/0260804, published Nov. 23, 2006, entitled “Surface Activated Downhole Spark-Gap Tool”, which is fully incorporated herein in its entirety by reference.

In one embodiment hereof, the source is a seismic source but it is to be understood that limitation to seismic sources is not intended. The seismic source 20 is permanently installed in the wellbore and is in power transferable communication with the power generation configuration 11 creating the system 10. Since the power generation configuration is parasitic, power is nearly always available to the seismic source 20 without the problem of batteries discharging or wirelines being removed from the wellbore, etc. This enables the system to conduct continuous or periodic queries of the wellbore and formation over the life of the well without impacting other well operations.

Changes in the signal reflection from the formation provide information about conditions associated with the maturing of the well such as, fluid fronts, washouts, time-varying reservoir volume, formation subsidence, etc.

While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation. 

1. A system for monitoring a wellbore comprising: a parasitic power generation configuration; a signal source in operable connection with the parasitic power generation configuration, the source being permanently positioned within the wellbore and capable of providing a signal that is receivable by a separate device to query condition of the wellbore.
 2. The system as claimed in claim 1 wherein the parasitic power generation configuration is a sucker rod dependent configuration.
 3. The system as claimed in claim 1 wherein the seismic source is a spark gap source.
 4. The system as claimed in claim 1 wherein the signal is seismic.
 5. A method for monitoring a wellbore comprising: generating power parasitically with a parasitic power generation configuration; applying the generated power to a permanently installed signal source; generating a signal from the signal source; reflecting the signal from the wellbore; receiving the reflected signal with a receiving device.
 6. The method as claimed in claim 5 wherein the generating of the signal is continuous over time.
 7. The method as claimed in claim 5 wherein the generating of the signal is periodic over time.
 8. The method as claimed in claim 4 wherein the signal is a seismic signal. 